<template>
  <view>

    <!-- 使用自定义的搜索组件 -->
    <my-search @click="gotoSearch"></my-search>

    <view class="scroll-view-container">
      <!-- 左侧滑动区域 -->
      <scroll-view class="left-scroll-view" scroll-y="true" :style="{height : wh + 'px'}">
        <block v-for="(item , i) in cateList" :key="i">
          <view :class="['left-scroll-view-item' , i === active ? 'active' : '' ]" @click="activeChanged(i)">
            {{item.cat_name}}</view>
        </block>
      </scroll-view>
      <!-- 右侧滑动区域 -->
      <scroll-view class="right-scroll-view" scroll-y="true" :style="{height : wh + 'px'}" :scroll-top="scrollTop">
        <view class="cate-lv2" v-for="(item2 , i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
          <!-- 动态渲染三级分类的列表数据 -->
          <view class="cate-lv3-list">
            <view class="cate-lv3-item" v-for="(item3 , i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <!-- 图片 -->
              <image :src="item3.cat_icon"></image>
              <!-- 文字 -->
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  import badgeMix from '@/mixins/tabbar-badge.js'
  export default {
    mixins: [badgeMix],
    data() {
      return {
        // 手机适配高度
        wh: 0,
        // 一级菜单数据
        cateList: [],
        // 一级菜单被选择的下标
        active: 0,
        // 二级菜单数据
        cateLevel2: [],
        // 滚动条距离顶部的距离
        scrollTop: 0
      };
    },

    onLoad() {
      // 获取手机适配高度
      const sysInfo = uni.getSystemInfoSync()
      this.wh = sysInfo.windowHeight - 50

      // 加载一级，二级菜单数据
      this.getCateList()
    },
    methods: {
      // 加载一级，二级菜单数据
      async getCateList() {
        const {
          data: res
        } = await uni.$http.get("/api/public/v1/categories")
        if (res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        // 为二级分类赋值
        this.cateLevel2 = res.message[0].children
      },

      // 修改一级菜单变动的内容
      activeChanged(i) {
        this.active = i
        this.cateLevel2 = this.cateList[i].children

        // 让 scrollTop 的值在 0 与 1 之间切换
        this.scrollTop = this.scrollTop === 0 ? 1 : 0
      },
      gotoGoodsList(item3) {
        uni.navigateTo({
          url: '/subpkg/goods_list/goods_list?cid=' + item3.cat_id
        })
      },
      gotoSearch(){
        // 调用 uni.setTabBarBadge() 方法，为购物车设置右上角的徽标
        uni.navigateTo({
          url: '/subpkg/search/search'
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;

    .left-scroll-view {
      width: 120px;
    }

    .left-scroll-view-item {
      background-color: #f7f7f7;
      line-height: 60px;
      text-align: center;
      font-size: 12px;

      &.active {
        background-color: #FFFFFF;
        position: relative;

        &::before {
          content: ' ';
          display: block;
          width: 3px;
          height: 30px;
          background-color: #C00000;
          position: absolute;
          top: 50%;
          left: 0;
          transform: translateY(-50%);
        }
      }
    }

    .cate-lv2-title {
      font-size: 12px;
      font-weight: bold;
      text-align: center;
      padding: 15px 0;
    }

    .cate-lv3-list {
      display: flex;
      flex-wrap: wrap;

      .cate-lv3-item {
        width: 33.33%;
        margin-bottom: 10px;
        display: flex;
        flex-direction: column;
        align-items: center;

        image {
          width: 60px;
          height: 60px;
        }

        text {
          font-size: 12px;
        }
      }
    }
  }
</style>